There are a fantastic variety of colors, shapes, and sizes in the cacti family, making them an appealing plant for avid gardeners looking for something unique or time-poor gardeners who need easy-care plants. These guys are tough, slow-growing, and live for many years. After acquiring your first cactus, you will probably want to grow your collection further. You can always purchase more, but why do that when you can propagate as many cacti as you like from your existing plants. In this article I will show you How to Propagate a Cactus.
What is Propagation
Propagation is a process that allows you to produce new plants from existing ones. Seeds from flowering, pollination, and fertilization are nature’s most prolific way to create new plants from old, but seeds are not the only way to grow your cacti collection.
As with some succulents, it’s possible to grow a new cactus from cuttings and offshoots, with offsets being one of the easiest and most popular methods, but not all varieties are suitable.
Cacti Not Suitable for Offset Propagation
Other methods of propagation will be more suitable for the following cacti species:
- Peanut cactus (Lobivia silverstrii)
- Miniature Rebutia
- Paper Spine Cactus (Tephrocactus)
- Large Echinocereus varieties
- Small Chin Cactus (Gymnocalycium)
There are also a few varieties that don’t produce pups or offsets, including:
- Members of the genus Ferocactus (large barrel-shaped types)
- Parodia cacti
- Members of the genus Astrophytum
It’s not usual for the above cacti to grow offsets, but there are situations, such as damage to roots, a wound, or frost damage, when they will. Cacti growers can take advantage of these situations, but they aren’t a reliable source of new plants.
How to Propagate a Cactus with Pups (Offsets)
Many cacti, but not all, propagate asexually, which means the parent plant produces offsets (often called pups) or lateral shoots. You can grow new plants by carefully removing the offshoots and transferring them to a suitable growth medium. Here are the steps you should follow for the successful propagation of a pup.
Wait until late spring or early summer to cut offsets off the main plant, which should be around 1.5 to 2 inches longs. Offsets growing higher up the plant are usually the healthiest and strongest.
You can propagate a cactus pup by using your hand to remove the pup. Carefully take the pup in your gloved hand and twist it gently until it disconnects. If that doesn’t work, you can resort to using a sharp knife, but disinfect it with boiling water or alcohol before cutting the pup off at the connection point. Disinfect your tools after each cutting to prevent the spread of disease and bacteria.
Ensure you remove any of the parent plant remaining on the pup, or it will rot and contaminate the offcut. Now that you successfully removed the offcut, you need to let it dry for around three days. To dry it, place the cutting vertically inside a container with drainage holes and keep it out of direct sunlight. The drying process is required to give the pup time to heal from any wounds that may cause it to rot after planting.
You can dip the cutting in rooting hormone before planting, but this is optional. Prepare a potting mix that is suitable for cacti and one that has excellent drainage. Place the dried cutting, cut part first, into the potting mix. Pack the soil around the pup to stop it from falling over and ensure that at least one-quarter of it is covered.
Quite often, especially in Echinopsis cacti, you will notice that your offcut will already have developed some roots. If it doesn’t, you can plant it in a soil and gravel mix. You should see it developing roots over a few days, but it shouldn’t take any more than a week. An alternative method for growing roots is to use a mix of sand, perlite, and charcoal.
Wait about a week before watering your new cacti, as this will reduce the chance of rot and infections taking hold.
How to Propagate a Cactus with Stem and Leaf Cuttings
You can also propagate a cactus with Stem and Leaf Cuttings, both are a popular method for growing a cacti collection that isn’t too dissimilar from offsets. Many cacti enthusiasts will use this method when their mature cacti are getting too big for the garden or as a way of saving a plant from disease.
As with offsets, wait until late spring, early summer, and about a week after watering the parent cactus. Choose the healthiest parts of the cactus and use a disinfected knife or sharp blade to get a nice clean cut. Slice the leaf or stem across its connecting point and dip the cut end into horticultural charcoal to prevent infection.
You must use a disinfected knife for this next step, which is to taper the end of the cactus into a point, much like sharpening a pencil. This step is important because the roots at the point of cutting will retract inside the plant.
An unsharpened cutting will only sprout roots from the cut side. Over time, the plant’s base will become too weak to hold a mature plant. Tapering the cutting to a point allows for an even distribution of roots and a stronger foundation for the mature plant.
Cuttings need time to dry, so leave them for a few days before potting. About 5 – 7 days should be sufficient for smaller ones, and 10 – 14 days for larger cuttings. You can hang them or place them vertically inside a container with drainage holes. Drying a cutting horizontally will cause roots to sprout on the underside, which will make it unsuitable for potting.
After about two weeks, you should see roots emerging from your cuttings, which is the sign that it’s time to replant your cactus into a standard growing substrate suitable for cacti.
How to Propagate a Cactus from Seeds
It’s also possible to propagate a cactus from seeds, but it’s a slow process with a much lower success rate. Cacti grown from seeds also take a lot longer to mature. However, despite the challenges, cacti grown from seeds are often your best plants because they have the opportunity to adapt to the conditions.
A few cacti, such as Echinocacti, Cereus, and Mammilaria, can create seeds by themselves (called cross-pollination), but others require pollination. You can do this by shaking the plant to loosen the pollen that will fall onto the stamen.
Tips for Growing Cacti from Seeds
Cacti seeds are tiny and easily lost, so use a white cloth to make them more visible when working with them. You will get the best results from seeds when you sow them in the early spring. While you can collect seeds from cacti fruits, it’s much quicker to purchase the varieties you like.
When Not to Propagate Cacti
Avoid propagation during a heatwave. The plants are stressed during these conditions and cutting and pruning for propagation will put them even more at risk.
Cacti go dormant during frost and freezing temperatures, so you won’t get the results you need, and your plants will be susceptible to disease and rot.